The experiments planned involve the use of in situ optical and electrophysiological techniques to answer specific questions concerning the metabolic effects of certain drugs which act on the central nervous system and by this means to work toward statements about the mechanisms by which some CNS agents exert their action. Previous work has established some of the relationships between energy metabolism in intact CNS and the electrical activity of these tissues in cats. In these investigations, the microfluorometric monitoring technique was used to measure the oxidation-reduction level of intramitochondrial NADH and the technique of reflection spectrophotometry was used to measure redox changes in the cytochromes together with changes in hemoglobin oxygenation state and the blood volume. Simultaneous to detection by these nondestructive optical techniques, extracellular potassium levels, steady potential shifts, ECoG and evoked potential activity are monitoried on the same tissue areas. Pharmacological agents which have an effect upon the working of the respiratory chain will thus be studied and the role of oxygen in these tissues will be considered. BIBLIOGRAPHIC REFERENCES: Rosenthal, M. and J.C. LaManna, Effect of ouabain and phenobarbital on the kinetics of cortical metabolic transients associated with evoked potentials, J. Neurochem., 24, 111-116, 1975. Lotham, E., J.C. LaManna, G. Cordingley, M. Rosenthal and G. Somjen, Responses of electrical potential potassium levels and oxidative metabolic activity of the cerebral neocortex of cats, Brain Research, 88, 15-36, 1975.